Poolbeg incinerator’s appetite for waste is a question of calories

The Poolbeg incinerator’s plume can appear red at night because of aviation warning lights on the chimney stacks. Photograph: Dara Mac Dónaill

John Daly, managing director at Covanta Ireland, knows the Poolbeg incinerator, or waste-to-energy plant to give it its official title, is not the most popular kid on the block.

“We get blamed for everything,” he says.

Given who the other kids on the block are, it’s easy to see why he might think this unfair.

“We are sitting here next to the waste water treatment plant, we’ve got two other power plants here, we’ve got a scrap yard across the road, but still, we get blamed for everything.”

Specifically, he references a fly infestation last summer, described by some locals as “biblical”. The Environmental Protection Agency (EPA) found “moderate fly numbers” in the waste intake building and bunker area, but Mr Daly says flies are not a new problem in the area. “It would be crazy to think we wouldn’t have flies, if everyone else in Ringsend and Irishtown had flies.”

Other accusations levelled against the plant are completely without foundation, he says. “People see the white plume coming out of the stack and think it’s smoke. It’s just like a kettle, it’s just water vapour.”

Flies

He says he finds this a more reasonable misconception than the flies, however.

“We’ve even had a few calls from people saying there are flames coming out of the stack, and I’ve thought: ‘What is that person on?’” This, he says, is a visual effect caused by the red aviation lights on the chimney stacks making the white plume appear red at night. “It’s funny, I never thought about it until I saw it myself, and I see what people are saying . . . It actually does look like a flame.”

More seriously, the plant has had some genuine failings to answer. A lime leak in the first week of operations resulted in 11 workers being hospitalised. “Any incident involving health safety is serious, but they’re all fine. They were all back working within a few days and they’ve all been compensated,” Mr Daly says.

The EPA took legal action against the firm in relation to a separate incident in the first week of operation, when it failed to comply with the terms of its environmental licence during testing of the plant. Earlier this year Covanta was fined €1,000 for the breaches.

However, one year on, these teething problems have been resolved and the plant is running safely and efficiently, Mr Daly says.

Dioxin and furan levels are 98.8 per cent below the European Union permitted limits; bottom ash, the main waste product left over after incineration is 16 per cent below what was predicted when planning permission was sought for the plant; and the number of trucks delivering waste to the plant is also 25 per cent fewer than originally planned.

Which all stacks up in favour of a potential expansion of the plant, but does not explain how the plant could go from taking in 600,000 tonnes to 690,000 tonnes of waste a year, without any need to physically expand the plant.

Calorific value

The answer mainly lies, Mr Daly says in the “calorific value” of the waste that’s arriving at the plant.

“The calorific value is about 10 per cent below what was originally envisaged. That is really because there’s been a very successful roll-out of the three-bin system in the intervening period,” he says. “The three-bin system has meant that paper and plastics, higher calorific value materials, are out of that system.”

As with food, the calorific value of waste is the amount of energy it contains. In terms of incineration, the easiest way to understand its relevance is to relate it to a domestic hearth, EPA enforcement inspector Pat Byrne says.

“If you put peat on an open fire it will burn more quickly than if you put coal on, and you’ll have to add more peat more often to keep the fire going – peat having a lower calorific value than coal.”

The same theory can be applied to any fuel source, and for an incinerator waste is a fuel. “Different types of waste will have different calorific values, for example the more damp waste is the lower the calorific value. It’s basically to do with the amount of heat you get from any quantity of waste,” Mr Byrne says.

The EPA is one body Covanta will have to persuade the plant can handle more waste. But before it applies to the EPA for a new licence, it must first secure planning permission from An Bord Pleanála.

Mr Daly hopes to make the planning application this year, with a view to getting an answer from the board in early 2019, ahead of the licence application to the EPA. If this process is successful, the company would hope to start taking the additional waste in 18 months’ time.

“The fact there is no construction, the fact there is no requirement to change the hours, the fact we’re not going to look to take any hazardous material and the fact we are so much below the original forecasted impacts of both transport and emissions I think stands in our favour.”

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